1. Field of the Invention
The present invention relates to a travelling vehicle system for carrying a cargo along a track to transfer the cargo to a rack or the like.
2. Description of the Related Art
There has hitherto been known a travelling vehicle system for allowing a travelling vehicle to travel along a rail hung on a ceiling to carry a cargo in the vicinity of the ceiling. The travelling vehicle is provided with a lift stage liftably hung by means of a hanging member. The travelling vehicle transfers the cargo by lowering the lift stage to a placement member of a rack arranged along a travelling route of the travelling vehicle.
The track is installed in accordance with arrangement of the rack. The track may be provided with a switching unit for switching a state of the track. For example, the switching unit switches a course at a divergence or a merge of the track (e.g., see Unexamined Japanese Patent Publication No. 07-6029). The travelling vehicle searches a travelling route in accordance with a cargo loading/unloading instruction and passes through a region provided with the switching unit (a switching region), to reach a target rack.